By default on Unix it should be in /usr/local/lib which is /lib. Most people will want to change this at compile-time with the –with-config-file-path flag. You would, for example, set it with something like:
And then you would copy php.ini-development from the distribution to /etc/php.ini and edit it to make any local changes you want.
On Windows the default path for the php.ini file is the Windows directory. If you’re using the Apache webserver, php.ini is first searched in the Apaches install directory, e.g. c:\program files\apache group\apache. This way you can have different php.ini files for different versions of Apache on the same machine.